Miscible flooding is considered unsuitable for some reservoirs in southeast Saskatchewan because of high CO2 minimum miscibility pressure or operating pressure constraints. Therefore, the effectiveness of near-miscible CO, injection was assessed for the Steelman reservoir in a laboratory study. The minimum miscibility pressures (MMP) were estimated for Steelman reservoir fluids with pure CO, and CO2-hydrocarbon gas mixtures, the partially flashed reservoir fluids and the dead oils with pure CO,. The results of MMP studies demonstrated (1) addition of ethane or propane can reduce CO2 MMP greatly; and (2) achieving a miscible CO, flood in the Steelman reservoir could be possible at a lower operating pressure than the measured CO, MMP, by partially depleting the reservoir. Asphaltene flocculation tests showed that, after the onset point, flocculation increased linearly with gas concentration, but that the presence of brine had a negligible effect. Three tertiary CO2 coreflood tests were conducted with Steelman reservoir fluids a;the reservoir temperature. These results showed that the microscopic displacement efficiency during the CO, injection stage improved with the operating pressure in the near-miscible region, but no dramatic change in oil recovery was observed with a change in operating pressure.